Evidence of central vestibulo-auditory dysfunction in atypical Cogan's syndrome: a case report.

Auditory and vestibular functions were investigated in a patient with atypical Cogan's Syndrome. The brainstem auditory evoked response revealed bilateral severe distortion of morphology and voltage diminution after potential I, greater in right ear recordings. Interwave latency I-III was increased bilaterally. Electronystagmographic studies showed nonfatigable direction changing positional nystagmus greater with right ear undermost and bilateral failure of optic suppression. Findings suggested bilateral pontocerebellar dysfunction. Correlation was found with the side of greater clinical manifestations. The patient had excellent recovery of auditory and vestibular functions with administration of corticosteroids within 2 weeks of the onset of hearing impairment. She was followed up with auditory and vestibular studies for 30 months.